First of all if you can afford a R9 380X then forget the GTX 960 because it doesn't really worth now. Both Nvidia and AMD have new GPUs which are better and lower price. And yes, R9 380X is a good GPU but if you want the best performance for price then get a RX 470 4GB. RX 470 is better than R9 380X and cheaper. I don't know whether its overpriced in your country but it's currently the best you can get.
Next best is GTX 1060 3GB, but lacks bit of VRAM but it'll barely make a difference.

I have FX-6300 Processor along with 8GB RAM and GTX750Ti for which card should I go next, I was thinking of GTX960 because X50 series are worst performers and X60, X70 and X80 are the best what do you think guys?

@mckracken ediditing videos is a processor heavy task youll need a good cpu n lots of memory. watch youtube videos of tech channels for good guide like linus techtips n their forums. post your query in the forum its a helpful community.

@tomcat i have hd7750 for the past year and i play at high mostly @720p but i feel it is getting outdated, because i see it struggle sometimes so i dont know how do cheaper gpus perform.
i got it at Rs.7000/$115.

This is a low profile edition of gt520. In this edition, the fan sounds less and electricity use less( I thought it reduce heat but not). So finally, IN WHICH GRAPHICS CARD I GET MORE FPS GT520 OR HD 6670

For The Budget HD 6670 Is the best
AMD Is BAD ? no AMD Is Good Then buy A R9 295 Then U Can MAX Anything But It Is Very EXpensive I Said HD 6670 Is Good For Low End Or Mid Gaming (Simple 720p Gaming) At The Low Price

#sakif What U Mean Last line ? my card is 520gt low profile (almost same as 520gt) ????????

@tomcat and hamzah, amd hd 6670 is 1gb. Test these sites {http://www.expertreviews.co.uk/graphics-cards/1284373/amd-radeon-hd-6670/specifications and http://www.geforce.com/hardware/desktop-gpus/geforce-gt-520/specifications.} Amd is bad at every side only batter in ddr5. I want only fps. And 1 thing my card is 520gt low profile (almost same as 520gt)

#sakif No Way That GT 520 Is just A entry LVL GPU That Card can't Play watch Dogs
#hamza5433 that GT 610 And GT 520 Are Just Same. Both Of Same Performance Both card can't Play New or Upcoming Games
I Hve GT 630 It is Very Btr Than GT 610 GT520 But I Can't Play Watch Dogs Without LAG

that Hd 6670 Is very Different If Compared to GT 520 Or gt 610 HD 6670 Can Play Watch Dogs And Some New games At Low Or Mid Sett And HD 6670 GDDR5 is Faster Than GDDR3 And That Card Can Play Most New And Upcoming Games At Mid Or Bit High Settings